Abstract

Using THz time domain spectroscopy we have observed both the real and the imaginary parts of complex dielectric constants in the far-infrared region for a glassy polymethyl methacrylate (PMMA). The intensity and phase of transmittance of PMMA were accurately measured in the frequency range between 5 and 110 cm(-1). The strong absorption appeared around a boson peak (BP) frequency, which was also observed by Raman scattering. The broad peak of an imaginary part related to BP shows a similar line-shape to the reduced depolarized Raman spectrum. (C) 2003 Elsevier Science B.V. All rights reserved.